JP2006016463A - Filament-reinforced polyamide resin molding material and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filament-reinforced polyamide resin molding material that gives molded products having excellent impregnating ability of polyamide resin into the reinforcing fibers, excellent mechanical strength and excellent strength deviation and surface appearance and provide a method for producing the same. <P>SOLUTION: This filament-reinforced polyamide resin molding material comprises a polyamide resin that has a melt flow rate of 20 to 120 g/10 min at 300°C under a load of 325 g according to JIS K7210 and reinforcing fibers treated with a surface treatment agent of 0.2 to 0.8 % mass where the content of the reinforcing fibers is 35 to 65 pts. mass per 100 pts. mass of the molding materials and they are arranged in almost the same direction and in almost the same length. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a long fiber reinforced polyamide resin molding material for producing a molded article having excellent mechanical strength, small variation and excellent surface appearance, and a method for producing the same.

  In the compound (FRTP) of the chopped strand and the thermoplastic resin which are reinforcing fibers, the chopped strand having a length of about 3 mm because it is melt-kneaded by a screw at the time of pellet preparation by an extruder or at the time of molding by an injection molding machine. Is finally broken to a critical fiber length level (about 0.2 mm). Therefore, it is difficult to control the fiber length, and there is a limit to improving the strength. In other words, considering the fiber breakage, it is common to reduce the fiber diameter in order to increase the strength, and since it is sufficiently melt-kneaded by an extruder during compounding, impregnation by thinning the fiber There is almost no deterioration in the properties, and even when reinforcing fibers having a certain thin fiber diameter are used, adhesion to the resin is relatively easy. The fiber diameter is preferably 10 μm to 13 μm.

  On the other hand, for the purpose of improving the strength by the fiber length, Patent Document 1 discloses a long fiber reinforced thermoplastic resin molding material obtained by impregnating a continuous long fiber reinforced fiber with a thermoplastic resin as a matrix resin and cutting it. It is disclosed. As a manufacturing method thereof, the matrix resin raw material is plasticized and melted by an extruder, and the molten resin is filled in the impregnation die and the continuous reinforcing fiber drawn from the wound body is passed through the impregnation die. . Thereby, the resin is impregnated into the reinforcing fiber composed of the strand, which is an assembly of filaments, and this is used as the molding material obtained by cutting the continuous reinforcing resin shaped by the nozzle.

The long fiber reinforced thermoplastic resin pellet disclosed in Patent Document 2 is for a window frame or door frame made of a thermoplastic resin, and the matrix resin has a melt flow index near the molding temperature of 5 g / 10 min or more. It is selected from polyolefin resins, polyamide resins, and thermoplastic polyurethane resins. Further, it is disclosed that the reinforcing fiber is an inorganic fiber or an organic fiber, the fiber diameter is a wide range fiber of 3 to 40 μm, and the content of the reinforcing fiber is 10 to 80% by weight. Yes.
JP-A-8-157610 JP 2003-25456 A

  However, in the molding material by the melt impregnation drawing method of the continuous fiber bundle and the resin, the impregnation property and the drawing workability of the matrix resin and the reinforcing fiber are important. Polyolefin, particularly polypropylene, is generally used as the matrix resin because the resin has good handleability such as a relatively low melting point. In order to increase the strength of such a molded product, in particular, to increase the impact strength, it is necessary to lengthen the remaining fiber length. As a result, the cutting length of the molding material is increased within a range where the molding workability is not impaired.

  On the other hand, as another means of increasing the strength, it is conceivable to reduce the fiber diameter of the reinforcing fiber. However, reducing the fiber diameter of the reinforcing fiber increases the number of fibers of the continuous fiber bundle, and the polyolefin Thus, when the adhesiveness with the glass fiber is inferior, the adhesiveness is inferior and the impregnation property of the resin is also inferior, and on the contrary, the mechanical strength and surface appearance of the molded product obtained from the molding material are lowered. For this reason, the reinforcing fiber used in the above-mentioned Patent Document 2 and the like has a relatively thick fiber diameter of about 17 μm as seen in the examples.

  On the other hand, when the polyamide resin is used as the matrix resin, the adhesion to the glass fiber is relatively good, and the strength improvement by reducing the fiber diameter of the reinforcing fiber is smaller than when the polyolefin resin is used as the matrix resin. I can expect. However, when ordinary polyamide resin is used as the matrix resin, the targeted strength increase of the molded product is not achieved. Instead, partial mechanical strength due to poor dispersion of reinforcing fibers in the obtained molded product is not achieved. Problems such as degradation and poor appearance occur.

  The object of the present invention is, when a polyamide resin is used as a matrix resin, the matrix resin is excellently impregnated into the reinforcing fiber, the resulting molded product is excellent in mechanical strength, and the strength variation and surface appearance of the molded product are excellent. An object of the present invention is to provide a long fiber reinforced polyamide resin molding material having excellent resistance and a method for producing the same.

  As a result of diligent research to achieve the above object, the present invention uses, as a matrix resin, a polyamide resin having a specific range as a fluidity at the time of melting, and a specific thin fiber diameter. It has been found that the above-mentioned object can be achieved by containing a specific amount of reinforcing fibers having and having been treated with a surface treatment agent having an adhesion amount in a specific range in the obtained molding material.

Thus, the present invention resides in a long fiber reinforced polyamide resin molding material having the following gist and a method for producing the same.
(1) A polyamide resin having a melt flow rate value of 20 to 120 g / 10 min at a temperature of 300 ° C. and a load of 325 g according to JIS K7210, a fiber diameter of 5 to 12 μm, and a surface treatment agent of 0.2 -0.8 mass% reinforcing fiber adhering, the reinforcing fiber is contained in an amount of 35 to 65 parts by mass per 100 parts by mass of the molding material, and arranged in substantially the same length as the length direction of the composition A long fiber reinforced polyamide resin molding material characterized by being made.
(2) The long fiber reinforced polyamide resin molding material according to the above (1), wherein the length of the long fiber reinforced polyamide resin molding material is 3 to 12 mm.
(3) The long fiber reinforced polyamide resin molding material according to (1) or (2), wherein the reinforcing fiber is a glass fiber.
(4) Reinforcing fibers obtained by arranging 2 to 12 fiber bundles in which 600 to 5000 single fibers having a fiber diameter of 5 to 12 μm are bundled so that the surface treatment agent adheres to 0.2 to 0.8 mass%. In accordance with JIS K7210, a polyamide resin having a melt flow rate value of 20 to 120 g / 10 min at a temperature of 300 ° C. and a load of 325 g is 35 to 65 per 100 parts by mass of the molding material. A method for producing a long-fiber reinforced polyamide resin molding material, wherein the composition is impregnated so as to have a mass part and the composition continuously drawn and shaped by a nozzle is cut.
(5) The manufacturing method according to (4), wherein the reinforcing fiber is a glass fiber and is cut into a length of 3 to 12 mm.

  Since the long fiber reinforced polyamide resin molding material in the present invention uses reinforcing fibers having a thin fiber diameter, when the content is the same, a larger number of reinforcing fibers can be contained, and the melt flow rate is in a specific range. When the polyamide resin having the above is used as the matrix resin and the surface treatment agent for reinforcing fibers has an adhesion amount within a specific range, the impregnation property of the matrix resin to the reinforcing fibers having a small fiber diameter is improved. Thereby, according to this invention, the long fiber reinforced polyamide resin molding material from which the molded article excellent in mechanical strength, intensity | strength dispersion | variation, and surface appearance property is obtained, and its manufacturing method are provided.

  Examples of the reinforcing fiber used for the long fiber reinforced polyamide resin molding material in the present invention include glass fiber, carbon fiber, and other ceramic fibers, and glass fiber is preferable. The (average) fiber diameter of the reinforcing fibers is 5 to 12 μm, and preferably 9 to 11 μm. If the fiber diameter is less than 5 μm, the production cost of the fiber is increased, which is not economically preferable. In addition, in order to obtain a specific fiber content, a large number of fibers are inevitably required, and the resin into the fiber. The impregnation property of is reduced, which is not preferable. On the other hand, when the fiber diameter exceeds 12 μm, the mechanical strength of the obtained molded product is lowered, which is not preferable. In the present invention, even if reinforcing fibers having a relatively small fiber diameter are used, the use of a surface treatment agent and a polyamide resin, which will be described later, provides excellent impregnation properties and adhesion to the reinforcing fibers of the polyamide resin.

  The reinforcing fiber used in the present invention is used in the form of a single fiber bundle having the specific fiber diameter. Usually, preferably a fiber bundle of 600 to 5000, particularly preferably 2000 to 4000 single fibers is prepared, and 2 to 12, particularly preferably 3 to 7 of these fiber bundles are drawn out. Are preferred. When the number of the above-mentioned fiber bundles is one, a large number of single fibers in the fiber bundle are required and the impregnation property is inferior, and this is not preferable. This is not preferable because a space for installing the winding body is required.

  When the reinforcing fiber is a glass fiber, in order to produce a fiber bundle from the glass single fiber, a surface treatment agent is applied immediately after spinning of the glass single fiber to form a fiber bundle. Various surface treatment agents can be used in this case, and among them, the surface treatment agent preferably contains a coupling agent in order to improve the adhesion to the polyamide resin as the matrix resin. As the coupling agent, a silane coupling agent such as aminosilane, epoxy silane, amide silane, azido silane, or acrylic silane, titanate coupling agent, or a mixture thereof can be used. Of these, aminosilane and epoxysilane are preferable, and aminosilane is particularly preferable.

  The amount of the surface treatment agent attached to the glass fiber is 0.2 to 0.8% by mass, and more preferably 0.25 to 0.60% by mass, based on the glass fiber containing the surface treatment agent. . When the adhesion amount is less than 0.2% by mass, the convergence property of the glass fiber bundle is inferior. In addition to clogging, the mechanical strength of the molded product is inferior. Also, if the adhesion amount exceeds 0.8% by mass, the fiber bundle will not be opened in the impregnation die, resulting in poor impregnation, and the reinforcing fiber will remain in the molded product in a state not impregnated with the polyamide resin. Variations in mechanical strength and poor surface appearance in the product are undesirable.

  The polyamide resin used in the present invention has a melt flow rate value of 20 to 120 g / 10 min, preferably 30 to 90 g / 10 min at a temperature of 300 ° C. and a load of 325 g, according to JIS K7210 as fluidity at the time of melting. Preferably it is. When the melt flow rate value is less than 20 g / 10 minutes, it becomes difficult for the polyamide resin to be impregnated into the fiber bundle in the impregnation die, and the mechanical strength of the resulting molded product varies, and the surface appearance is improved. Decreasing and not preferable. When the melt flow rate value exceeds 120 g / 10 min, the impregnation property is improved, but the mechanical strength of the resin itself is lowered, and the mechanical strength of the resulting molded product is inferior.

  The polyamide resin is not particularly limited as long as it is fluid. The polyamide resin such as polyamide 6, polyamide 66, polyamide 46, polyamide 11, polyamide 12, polyamide 6-10, acrylonitrile-butadiene-styrene copolymer, Mixtures or alloyed with other resins such as styrene-butadiene copolymer can also be used. Of these, polyamide 6 and polyamide 66 can be preferably used. In order to impart the properties of polyamide 6 and polyamide 66 in a well-balanced manner, an alloy that has been alloyed can be particularly preferably used.

  In the present invention, a long fiber reinforced polyamide resin molding material is produced by impregnating the glass fiber bundle subjected to the above surface treatment with a molten polyamide resin. That is, the glass fiber bundle is drawn out of the impregnation die to which the extruder is attached, and is impregnated with the molten polyamide resin. Several bars are installed in the impregnation die, and the glass fiber bundle is opened as it passes through it.

  On the other hand, the polyamide resin plasticized and melted preferably at 270 ° C. to 350 ° C. is fed into the impregnation die, impregnated into the opened glass fiber bundle, and the glass fiber bundle impregnated with the polyamide resin is impregnated from the extruder. Excess polyamide resin is squeezed by a die or the like at the die exit and cooled. The plasticizing temperature of the polyamide resin is preferably adjusted according to the melt flow rate value according to the glass fiber content and the degree of impregnation.

  In order to produce a long fiber reinforced polyamide resin molding material in the present invention, the above-mentioned temperature range is sufficient as the plasticizing temperature of the polyamide resin. However, impregnation and productivity and glass in the finally obtained molded article are sufficient. In order to further improve the dispersibility of the fibers, 290 ° C to 340 ° C is particularly preferable. The glass content in the long fiber reinforced polyamide resin molding material thus obtained is preferably 35 to 65% by mass, and more preferably 40 to 60% by mass. When the glass content exceeds 65% by mass, the amount of glass fiber increases and the impregnation with the polyamide resin tends to be insufficient. On the other hand, if it is less than 35% by mass, the reinforcing effect of the glass fiber is not remarkable, and an undesirable effect appears in terms of cost.

  Next, the glass fiber bundle impregnated with the long fiber reinforced polyamide resin is preferably cut into a length of 3 to 12 mm, particularly preferably 5 to 10 mm, by a cutting machine. When the cutting length is less than 3 mm, the obtained long fiber reinforced polyamide resin molding material is easily cracked in the vertical direction, causing problems such as fluffing. On the other hand, if the cutting length exceeds 12 mm, the dispersibility of the glass fiber during molding is lowered, the mechanical strength of the resulting molded product varies, and appearance defects due to non-dispersion in the molded product surface appearance are likely to occur. Become.

  The produced long fiber reinforced polyamide resin molding material is used for molding alone or mixed with other resins. The resin mixed and used in this case is not necessarily the same as the polyamide resin contained in the long fiber reinforced polyamide resin molding material, but when the same polyamide resin is used, It is preferable because of its excellent surface appearance.

  Although the molding method in the manufacturing method of the molded article using the long fiber reinforced polyamide resin molding material of the present invention is not particularly limited, preferably injection molding is used. In the present invention, it is preferable that the reinforcing fibers in the molded product are dispersed with a weight average fiber length of preferably 2 mm or more. In order to manufacture such a molded article, it is preferable to use a molding machine equipped with a screw having a deep groove and a nozzle having a large diameter.

  The long fiber reinforced polyamide resin molding material of the present invention can contain an appropriate additive in order to impart desired characteristics to the molded product within a range that does not significantly impair the object of the present invention. For example, antioxidants, stabilizers such as ultraviolet absorbers, antistatic agents, coloring agents such as dyes and pigments, lubricants, plasticizers, and inorganics such as glass flakes, glass powder, glass beads, mica, alumina and carbon powder An appropriate amount of the material may be blended. Also, a compound selected from a lubricant such as a metal salt of a fatty acid effective for improving the fluidity of the molding material during molding and homogenizing the reinforcing fiber, for example, a salt of a fatty acid having 28 to 30 carbon atoms and a metal such as lithium. Can be blended in an appropriate amount.

  The present invention will be described more specifically with reference to the following examples. However, the present invention should not be construed as being limited to such examples. In the following examples, Examples 1 and 2 are examples of the present invention, and Examples 3 to 6 are comparative examples.

In the examples and comparative examples, the glass fiber bundle and the polyamide resin used for the production of the long fiber reinforced polyamide resin molding material are as follows.
・ Glass fiber bundle (glass roving): A predetermined amount of surface treatment agent, polyurethane resin, ethylene-maleic acid copolymer, and silane coupling agent are applied to glass fibers having a fiber diameter of 10 μm and 16 μm immediately after spinning from bushings. It was manufactured by doing. The number of single fibers in one fiber bundle was adjusted to be 2400 when the average fiber diameter was 10 μm and 4000 when the average fiber diameter was 16 μm.
Polyamide resin: A commercially available polyamide 6 resin having a melt flow rate value of 90 and 16 at a temperature of 300 ° C. and a load of 325 g according to JIS K7210 was used.

  Using the above materials, the long fiber reinforced polyamide resin material produced by the method shown below was injection molded, and the surface appearance, tensile strength, bending strength, and impact resistance of the molded product were evaluated.

・ Manufacture of long fiber reinforced polyamide resin molding materials:
While opening the glass roving with an impregnation die and pulling it, plasticizing with an extruder, melting and infiltrating the melt of the polyamide resin sent to the impregnation die, and then taking it as a strand through the shaping die, After cooling, Example 2 was cut with a cutting machine into a length of 12 mm, and the others were cut into a length of 8 mm. Plasticization and melting temperature is 290 ° C.

・ Manufacture of molded products:
Using the long fiber reinforced polyamide resin molding material obtained above, a cylinder temperature of 300 ° C. and an injection speed of 12.7 mm / in accordance with JIS-K8921-2 using a long fiber injection molding machine and a multi-purpose test piece mold. A multi-purpose test piece (JIS K7139) for physical property testing was produced by injection molding under the conditions of sec.

・ Evaluation of molded products:
Using the molded product obtained above, the tensile strength was evaluated according to JIS-K-7161, the bending strength was evaluated according to JIS-K-7171, and the notched Izod impact strength was evaluated according to JIS-K-7110.

Further, the fiber dispersibility was obtained by molding 10 flat molded products having a length of 60 mm, a width of 60 mm, and a thickness of 2 mm using the long fiber injection molding machine, and the dispersion state of the fibers on the surface, particularly the presence or absence of undefined bundles, The appearance of the surface of the molded product was observed visually. The evaluation of the results was judged as follows.
◎ No undefined bundles of long fibers are observed in all 10 sheets ○ Undissolved bundles of long fibers are rarely seen × Undefined bundles of long fibers are scattered ×× A defibrated bundle can be seen on all 10 sheets

  As is clear from Table 1, compared with Examples 1 and 2, Examples 4 to 6 have a fiber diameter of 16 mm and good dispersibility, but the strength is low. In Example 3, the fiber diameter is low. Although it is 10 mm, it can be seen that the melt flow rate value of the polyamide resin is low and the surface treatment agent has high adhesion, so that the dispersibility (surface appearance) is poor. Thus, Example 1 and Example 2 are excellent in mechanical strength and surface appearance, compared with Examples 3-6, although glass content rate etc. are equivalent.

Claims (5)

  In accordance with JIS K7210, a polyamide resin having a melt flow rate value of 20 to 120 g / 10 min at a temperature of 300 ° C. and a load of 325 g, a fiber diameter of 5 to 12 μm, and a surface treatment agent of 0.2 to 0.00. 8% by mass adhering reinforcing fibers, the reinforcing fibers are contained in an amount of 35 to 65 parts by mass per 100 parts by mass of the molding material, and arranged in substantially the same length as the length direction of the composition. A long fiber reinforced polyamide resin molding material characterized by the above.   The long fiber reinforced polyamide resin molding material according to claim 1, wherein the length of the long fiber reinforced polyamide resin molding material is 3 to 12 mm.   The long fiber-reinforced polyamide resin molding material according to claim 1 or 2, wherein the reinforcing fibers are glass fibers.   Reinforcing fibers obtained by arranging 2 to 12 fiber bundles obtained by bundling 600 to 5000 single fibers having a fiber diameter of 5 to 12 μm so that the surface treatment agent is attached to 0.2 to 0.8 mass% are JIS K7210. , A polyamide resin having a melt flow rate value of 20 to 120 g / 10 min at a temperature of 300 ° C. and a load of 325 g is 35 to 65 parts by mass per 100 parts by mass of the molding material. A method for producing a long fiber reinforced polyamide resin molding material, comprising impregnating the composition and cutting the composition continuously drawn and shaped from a nozzle.   The manufacturing method according to claim 4, wherein the reinforcing fiber is a glass fiber and is cut into a length of 3 to 12 mm.